Seamless handoff scheme for 4G mobile systems based on IP and OFDM

The goal of 4G mobile systems is to provide enhanced services with high data rates, and integrated and converged services with IP-based networks. In order to satisfy the high data rate requirement and support multimedia efficiently, OFDM (orthogonal frequency division multiplexing) has been considered for the modulation and multiple access scheme in 4G systems. Therefore, we propose an efficient and practical seamless handoff scheme for 4G mobile systems based on IP and OFDM. The goal of the seamless handoff scheme is to minimize handoff delay in providing a seamless connection. The seamless handoff scheme obtains the physical channel for handoff in a contention-free manner with pre-synchronization and pre-forwarding IP contexts. As a result, it thoroughly decreases physical channel blocking delays as well as IP layer context-switching delays during handoff.